Photoelectric cells of the layer type and method of producing the same



E. PRESSER 2,161,786

PHOTOELEGTRIC CELLS OF THE LAYER TYPE AND METHOD OF PRODUCING THE SAME June 13, 1939.

V Filed April 2, 1957 Fig! Zr W .lffak/ieya Patented June 13, 1939 PHOTOELECTRIC CELLS OF THE LAYER TYPE AND METHOD OF PRODUCING THE SAME Ernst Presser, Berlin-Dahlem, Germany Application April 2, 1937, Serial No. 134,685 In Germany April 8, 1936 3 Claims. (c1. 13s-s9) nium in crystalline form or another element of the sixth group of the periodic table of elements with or without materials of higher conductivity mixed thereto and a translucent homogeneous 10 covering layer of conducting material in finely divided form upon and in intimate contact with the crystalline surface oii said light-sensitive layer. Because of the extreme thinness of the covering layer it is rather difficult to connect 15 wires or other conductors thereto for conducting an electric current to or from the cell, and this difficulty is even increased when the conductors are, as usual, simply pressed against said covering layer, since the even relatively feeble me- O chanical pressure injures the thin covering layer at the spot where it is applied so that the electric contact will be uncertain.

Therefore it has been proposed to provide such covering layers with conductive. reinforcing ribs" adapted to be connected to a conductor by soldering or by pressure. Preferably only the margin or a part of the margin of the covering layer is provided with such a reinforcing rib so as to have only the least possible reduction of the ef- 3U fective area of the cell. In certain cases it is even sufficient to provide only little spot-like reinforcements on the marginal portion of the covering layer. The reinforcing ribs or spots are usually applied to the cell by spraying metal upon the predetermined parts of it; the spraying can take place either before or after' the application of the thin covering layer.

The photoelectric cells of the type referred to are usually protected by a layer of translucent 40 varnish against injurious atmospheric influences.

Since the varnishes which are best adapted for this purpose do not lend themselves well for spraying, the cells are varnished by immersing them into the varnish, and therefore the reinforcing ribs or spots'are also covered by the'varnish. However, since in most cases the electric connection of the cell to the conductors to be connected to it is efiected by pressure contacts, the varnish layer covering the reinforcement ribs or spots causes difliculties by impairing the desired intimate contact between the contact pieces and the reinforcement ribs or spots.

According to my invention this drawback is eliminated by sprayiniupgmthese parts of the ribs, conducting material in such manner as to cause the varnish layer to be pierced by the sprayed material, thus rendering a conductive connection between the conducting layers under and upon thevarnish layer. As the conducting 5. layer sprayed upon the varnish layer does not need any protection against atmosphere influences, it gives the possibility of making a safe and effective electric contact between the thin translucent covering layer under the varnish layer and pressure contact pieces applied to the varnished surface of the cell.

Of course it is not necessary to spray conducting material upon all those parts of the varnish layer which cover reinforcing ribs of the translucent covering layer; in many cases it may suffice to apply sprayed conducting material only to a fraction of those parts of the varnish layer. For example, the reinforcing rib mayhave'the formof a ring covering the marginal portion of the translucent covering layer while the conducting material piercing the varnish layer can be sprayed upon the same in the form of round spots distributed along the ring-shaped reinforcing rib.

My invention is illustrated in the accompanyingdrawing by way of example.

Fig. 1 is a cross section of a photoelectric cell according to the invention, and Fig. 2 is a plane view thereof.

A metallic base plate I carries a light-sensitive layer 2. The marginal portion of this layer is covered by a metallic ring-shaped reinforcing rib 3 which is applied to the layer 2 by spraying. This reinforcing rib 3 may be produced by placing a mask having a ring shaped opening over layer 2 and spraying metal into the ring-shaped opening until an amount of metal is deposited upon the exposed portion of layer 2 which is suflicient to produce the desired height of rib 3. 40 A somewhat rounded section of the rib' 3 will be produced if more particles are sprayed upon the central portion of the section of the rib than upon the outer portions of such section and such rounded section may be produced when employing a mask, for such mask will shade the side portions of the annular opening more than the central portion when the metal is being sprayed. The central portion of the-layer 2 is covered by a thin translucent conducting covering layer 4 which is in conductive contact with the rib 3. The base-plate l is theone electrode and the coveringlayer 4 is the other electrode of the cell. The covering layer land. the metallic rll: 3 are covered by a varnish layer 5 protecting them against atmospheric influences. Upon that part of the varnish layer I which covers the ringshaped reinforcing rib l a further correspondmay be'ea'sily accomplished as the speed of the sprayed metal particles with which they meet' the varnish layer may be easily regulated by varying the strength'ot the gaseous stream carrying the particles and be increasing or decreasing the distance of the spraying device from the g contact with the surface of said light-sensitive cell in such a manner that they do not penetrate the varnish but merely cover it or in such a manner that they penetrate the varnish. As soon as the varnish layer is penetrated by the metal particles, a conductive contact is made between the rib s and that portion of the metal particles which remains in the varnish, for the metal partlcles force their way through the varnish in the manner innumerable bullets would and thereby build up an emcient conductive contact through the varnish layer; The metallic layer 8 can now be used as one of the terminals of the cell while the covering layer 4 is hermetically. sealedby or the layer type which conslsts in providing the translucent conductive covering layer with reinforcing ribs of, conducting material in contact with said covering layer, covering the-said covering layer and reinforcing ribs with a thin translucent layer of varnish, and spraying upon those parts 01' said varnish layer which cover the said reinforcing ribs, conducting material under such conditions that the varnish layeris pierced by the sprayed material. v

2. Photoelectric cell of the layer type comprising a base plate, a layer of light sensitive material upon said base plate,- a translucent conducting covering layer upon and in intimate layer, reinforcing ribs of conducting material in contact with said covering layer, a layer or varnish upon said covering layer and said reinforcing ribs, and a further layer of conducting material upon those parts of the varnish layer which cover the said reinforcing ribs, said further layer or conducting material being inconductive -connectlon with the'sald reinforcing ribs.

3. Photoelectric cell according to claim 2,

- wherein said i'urtherlayer of conducting material partly penetrates through the said varnish layer and thus is in conductive connection with the said reinforcing ribs.

ERNST msssna. 

